Information system of marsh ecosystem is a specialized information system.Setting up the information system of marsh ecosystem in the Sanjiang Plain region has an important significance in comprehensively analyzing and dynamicly moritoring marsh environment as well as in making a regional territory resource managerment and national economy program. The information system of marsh ecosystem contains two subsystems. the marsh resource and the geographic environment in marsh area.The data mainly come from various maps,governmental reports and field investigations.The data were approved by the governmental department concerned.It has an extensive practicality and authority.Before the data were input the data base,the process of classification and standardization had been made and then a code was given to the data according to the meaning of each code figure. The system adopts CCDOS as the operating system.It was operated by the way of menu control.The mainly used software is dBASE-Ⅲ,the prograruing languages of BASIC,FORTRAN andAssembler were used to extend the system functions.In technology,a particular attention was placed on the identity of map and data.It not only stressed the relation between maps and data,but also strengthened the space position of the data.It is convenient for the users in different ways.